Freestyle ported big bores which exhaust is best from experience?

im in the market for b pipe and want some ideas from personal experience on which b pipe is better for 865+ engines. pfp is outta the question one reason i like a little larger tank and two the price. between mod or limited which is better. its a $30 dif. some say bigger bore = bigger chamber and others say mod for bigger bore modified engines. any personal experience would be appreciated. thanks
 
c4 chamber is out of the question. does not look like it will work with my tank. so i guess the final consensus is mod chamber? no one else has any input. if pfp pipe (with its big chamber )is so good why would you put a smaller chamber b pipe on a big bore? i guess thats were im confused.
 

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Exactly what tank in what hull are you using? I thought that C4 chamber is supposed to work with an OEM SJ tank.
The B-Mod chamber, being shorter than the B-limited chamber, hits a little later that the limited but carries power a little further up. In bigger motors, you have more bottom end power anyway, so you go with a mod chamber to better take advantage of all the power the motor has to offer.
 
i have a js 550 tank. my hull is a 300sx thats pretty much a bob with engine set back as far as possible. me ebox is above tank and the battery is between tank and engine so in the pics it looked like the c4 would hit something either battery or tank. i know a b pipe fits for sure. ill go with the mod chamber its cheaper anyway. i used to run coffman but i figured that pipe was way to small.
 

MikeyB

H2O-Addict®
Location
Michigan
Exactly what tank in what hull are you using? I thought that C4 chamber is supposed to work with an OEM SJ tank.
The B-Mod chamber, being shorter than the B-limited chamber, hits a little later that the limited but carries power a little further up. In bigger motors, you have more bottom end power anyway, so you go with a mod chamber to better take advantage of all the power the motor has to offer.

With a bigger motor aren't you going to have more power everywhere, so you would run a chamber with a length that would tailor to where you want to focus your power?
 

waxhead

wannabe backflipper
Location
gold coast
With a bigger motor aren't you going to have more power everywhere, so you would run a chamber with a length that would tailor to where you want to focus your power?
Spot on/ Use a limited chamber. It will make smoother and power with a better hit down low
 
the c4 will fit in a rickter fs2 with a setback motor,and stock tank,granted its not much fun to get in there but does work very well
 

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
You want the limited chamber, Another thing to consider is boring out your b-pipe


Art had Andrew run a bored Limited on his stroked 888

Huh. He must have done a turn about on this then in the past couple of years.
I've run both chambers back to back in the past and IMHO, the power delivery on the limited ran out too quickly.
 

munki63

Epoxy is my duct tape
Location
Canada
I did limited vs mod on my old 771 and the limited destroyed the mod pipe thru the entire power band, granted its not an 865, Howerever maybe the question could be stroke size not total cc, Or maybe I'm wrong but I'm sure XJCrawler is running a Limited Chamber
 

swapmeet

Brotastic
Location
Arlington TX
I would imagine the port timing also makes a difference from engine to engine.

x2 on boring out the B-pipe. I assume you're going to buy a new exhaust system?
 
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